Dynatrace Load - Dynatrace Load lets you test the performance of web and mobile applications with the realism of load generation from the cloud.
Real Load - Real Load - A REST, SOAP, HTML, HTTP, Powershell, SQL performance test tool
Blackfire.io - Blackfire empowers all PHP developers and IT/Ops to continuously verify and improve their app’s performance, throughout its lifecycle, by getting the right information at the right moment.
LoadStorm - Load test websites, web apps, APIs, and mobile apps via the cloud. Use scripts to simulate user behavior for up to a million virtual users. Try it for free!
Apache JMeter - Apache JMeter™.
NewRelic - New Relic is a Software Analytics company that makes sense of billions of metrics across millions of apps. We help the people who build modern software understand the stories their data is trying to tell them.